Production of titanium tetraiodide



Patented Apr. 2 4, 1951 PRODUCTION OF TITANIUM TETRAIODIDE Warren B. Blulnenthal, Niagara Falls, N. Y., as-

signor to National Lead Company, New York, N. Y., a corporation of New Jersey No Drawing. Application December 17, 1948, Serial No. 65,965

The present invention relates'to the extraction of elementary titanium from its oxide ore and particularly to a method in which oxide minerals of titanium are reduced with aluminum with production of a titanium aluminum alloy with subsequent formation of titanium iodide from such titanium aluminum alloy.

Although titanium is the ninth most abundant of the structural metals occurring in the earths crust, and although metallic titanium has the highest tensile strength per unit of weight of all pure metals, the procedures heretofore practiced for obtaining pure metallic titanium from its oxide ores had serious limitations since such procedures are extremely costly and only small quantities of the metal were actually produced.

One of the most wide spread methods for winning titanium from its ores is chlorination of an oxide ore of titanium in the presence of carbon and at elevated temperature whereby titanium tetrachloride is obtained. The titanium tetrachloride is then reduced with metallic sodium, metallic magnesium, or other powerfully reducing material. The product so obtained, crude titanium metal, is generally in the form of powder or granules which requires further processing to free it of foreign substance, particularly oxygen or nitrogen or both, in order that the resultant metal may possess ductility.

It is an object of the present invention materially to simplify the conversion of titaniferous substances to titanium tetraiodide which latter may then be converted to titanium metal either by heating to high temperature or by reduction with hydrogen gas at elevated temperatures.

In broad aspect, the invention comprehends first the production of a titanium-aluminum alloy by the so-called thermit reaction. That is, the titaniferous oxide ore, as for instance rutile, anatase, or ilmenite, is heated to a high temperature in the presence of suflicient powdered or granulated aluminum to reduce the oxide to metal and to form with that metal an aluminumtitanium alloy with as high a content of titanium as possible. In general, the thermit reaction will produce from high grade rutiles, that is, rutile containing about 60% titanium metal, a titaniumaluminum alloy of in the neighborhood of about '7 0% titanium and, as the object of the invention is to facilitate the production of metallic titanium, it will be advantageous to Work for the production of titanium-aluminum alloys with a titanium content as high as practicable consistent with good recovery of titanium values from the ore employed.

7 Claims. (Cl. 23-87) .nium tetraiodide and aluminum iodide. found that this mixture of metal iodides may be iodide.

The titanium aluminum alloy so formed is then changed in accordance with the present inven' tion to the metaliodides of titanium and aluminum. Thischange is effected by a novel treat ment of the titanium-aluminum alloy with iodine in the presence of a non-polar solvent which is a solvent for both iodine and the metal iodides. Such non-polar solvents include carbon disulfide, carbon tetrachloride, benzene, and toluene, among others. It is preferred to employ carbon disulfide as the non-polar solvent since the solubility of iodine therein is somewhat greaterthan the solubility of iodine in the other non-polar solvents and, therefore, due to higher concentration of dissolved iodine, the reaction time is diminished. I have found it advanta eous to carry out the reaction of iodine upon the titanium-aluminum alloy in the presence of a nonpolar solvent under refluxing conditions since the formation of the metal iodides proceeds with evo: lution of heat and the temperature of the mixture will be raised to the boiling point of the nonpolar solvent.

After the formation of the metal iodides is completed, the non-polar solvent is removed from the reaction mixture generally by distillation, leaving a residue of anhydrous iodides of tita- I have resolved into its components by determining the amount of aluminum iodide present and adding to the mixed iodides potassium iodide in such proportion that 1 mol of potassium iodide is present per mol of aluminum iodide. Upon heat.- in this mixture of titanium iodide, aluminum iodide and potassium iodide, titanium tetraiodide, together wth any free iodine which may be present, is volatilized while all of the aluminum iodide, together with the potassium iodide added, remains in theresidue as potassium aluminum The pure titanium tetraiodide obtained by this novel procedure may now be converted to :pure titanium metal by conventional methods While the iodine maybe recovered from the various iodides and reused in the process.

The followin example is merely illustrative of the principles of the invention and is not given as limitative thereof.

A sample of rutile concentrate containing 94% "TiOz was mixed with powdered and granulated aluminum metal, together with the usual starters, etc., used in the conventional thermit reduction as, for instance, chlorates and magnesium starter fuse in the proportions as follows:

. was induced.

To insure completion of the formation of the metal iodides with the titanium, the reaction vessel may be heated after the initial violence of the reaction has been spent. The color of the reaction mixture, initially purple, changes to a maroon upon completion of the reaction. The reaction will be found to be complete in about to minutes.

After the reaction has been completed, the non-polar solvent is removed from the metal iodides in any convenient fashion, as by distillation, and recovered. The distillation temperature should be maintained substantially below that at which titanium tetraiodide boils, i. e., be low about 250 C. If all the alloy has not been attacked and dissolved, additional iodine and solvent may be added to the residue and the procedure repeated. 7

After removal of the non-polar solvent, the residue consists of titanium tetraiodide, aluminum triodide and free iodine. These materials were found in the residue in the following amounts: titanium tetraiodide68.2%, aluminum iodide-41.2%, 0.2% insoluble matter, and the remainder free iodine.

The titanium tetraiodide is distilled from the other iodides by fixing the aluminum iodide by the addition of potassium iodide.

To an amount of the mixed iodides obtained as outlined above, containin 41 parts of aluminum iodide, there was added 17 parts of potassium iodide. tort to a temperature at which titanium tetraiodide is evolved freely, i. e., above about 250 C. A. small amount of uncombined iodine together with all the titanium iodide distills off and ,may be condensed. Metallic titanium may then be obtained in any conventional Way from the iodide, either by heat decomposition or by reduction.

The process of the present invention proceeds smoothly and easily and is of advantage since substantially all the reagents employed may be recovered and recycled for reuse in the process.

What is claimed is:

1. In the recovery of titanium tetraiodide from its oxide ores, the steps which comprise reducingthe ore with aluminum to produce a titaniumaluminum alloy, reacting said alloy with iodine in the presence of a non-polar solvent to produce a mixture of iodides of titanium and aluminum and thereafter heating the mixed iodides of titanium and aluminum in the presence of potassium iodide to distill off titanium iodide.

2. In the recover-y of titanium tetraiodide from its oxide ores, the steps which comprise reducing the Ore with aluminum to produce a, titaniumaluminum alloy, reacting said alloy with sulfi- This mixture was heated in a recient iodine dissolved in a non-polar solvent to change titanium and aluminum metal values of the alloy to iodides, thereafter heating said iodides in the presence of potassium iodide to volatilize titanium iodide and collecting the latter.

3. In the recovery of titanium tetraiodide from its oxide ores, the steps which comprise reducing the ore with aluminum to produce a titaniumaluminum alloy, reacting said alloy with sufiicient iodine dissolved in a non-polar solvent to change titanium and aluminum metal values of the alloy to iodides, adding to said iodides sufficient potassium iodide to form potassium aluminum iodide with the aluminum iodide present, thereafter heating said mixture of iodides to volatilize titanium tetraiodide and collecting the latter.

4. In the production of titanium tetraiodide the steps which comprise treating a titaniumaluminum alloy with sufficient iodine in the presence of a. non-polar solvent to form iodides of titanium and of aluminum, removing the solvent from the mixture of metallic iodides, adding to the latter sufiicient potassium iodide to form potassium aluminum iodide with the aluminum iodide content thereof and thereafter heating the mixed iodides to a temperature sufficiently high to volatilize titanium tetraiodide and collecting the latter.

5. In the production of titanium tetraiodide the steps which comprise treating a titaniumaluminum alloy with sufficient iodine in the presence of a non-polar solvent to form iodides of titanium and of aluminum and thereafter heating the mixed iodides of titanium and aluminum' in the presence of potassium iodide to distill off titanium iodide.

6. Method according to claim 5 wherein the non-polar solvent is carbon disulfide.

'7. In the production of titanium tetraiodide the steps which comprise treatin a titaniumaluminum alloy with sufficient iodine in the presence of a non-polar solvent to form iodides of titanium and of aluminum, removing the solvent from the mixture of metallic iodides, adding to the latter sufiicient potassium iodide to form a compound with aluminum iodide of a boiling point above about 250 C. and thereafter heating the mixed iodides to about 250 C. to volatilize titanium tetraiodide and collecting the latter.

WARREN B. BLUMENTI-IAL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,455,005 Kirkpatrick May 15, 1933 FOREIGN PATENTS Number Country Date 551,525 Great Britain Feb. 26, 1943 OTHER REFERENCES A Comprehensive Treatise on Inorganic and Theoretical Chemistry, by J. W. Mellor, vol. 5, pp. 327-32 9, and vol. '7, pp. 21 and 89. Longmans, (Green and Co., N. Y., publishers. 

1. IN THE RECOVERY OF TITANIUM TETRAIODIDE FROM ITS OXIDE ORES, THE STEPS WHICH COMPRISE REDUCING THE ORE WITH ALUMINUM TO PRODUCE A TITANIUMALUMINUM ALLOY, REACTING SAID ALLOY WITH IODINE IN THE PRESENCE OF A NON-POLAR SOLVENT TO PRODUCE A MIXTURE OF IODIDES OF TITANIUM AND ALUMINUM AND THEREAFTER HEATING THE MIXED IODIDES IF TITANIUM AND ALUMINUM IN THE PRESENCE OF POTASSIUM IODIDE TO DISTILL OFF TITANIUM IODIDE. 